1. Field of the Invention
This invention relates to a virtual media system, such as virtual media in an IKVM (KVM-Over-IP) system. In particular, it relates to a virtual media system with folder-mount function.
2. Description of the Related Art
A KVM (keyboard video mouse) switch is a device that allows one or more user consoles to selectively communicate with one or more computers connected to the KVM switch as if the user console is directly plugged into the computer. In a conventional KVM switch configuration, one or more consoles (each including a keyboard and/or mouse and a display device) are connected to the KVM switch by cables, and a plurality of computers are connected to the KVM switch by cables. A network-enabled KVM switch (also referred to as a network-based or IP-based KVM, IKVM, or KVM over IP) uses a network protocol (e.g. TCP/IP) as its communication protocol, and can be accessed from any computer on a network (such as the Internet, an Intranet, a WAN, a LAN, Ethernet, a wireless network, etc.) A remote operator can log in to an IKVM switch from anywhere on the network via a browser, and can exchange keyboard, video and mouse signals with any one of the computers connected to the IKVM switch. An IKVM switch has a controller, referred to as an IKVM controller, which is connected to a controller/circuit/chip (NIC) for handling packets containing keyboard and mouse signals received from a remote console on a network, and transmits packets containing video signals and other signals to the network via the NIC.
Virtual media is a technology for sharing files in a system comprising two computers connected via a network such as the Internet, so that a storage device physically connected to the first computer can be accessed by the second computer as if the storage device is located on the second computer. Virtual media technology has been used in KVM switch systems where a client computer accesses an IKVM switch via a network to control a server computer connected to the IKVM switch. Using the virtual media technology, a storage device physically connected to the client computer can be presented to the server computer as virtual media.
For example, U.S. Pat. No. 7,260,624 describes a system where a local computer 102 and a remote computer 120 are connected via a network 118, with an interaction device 110 connected between the local computer and the network. The patent describes: “In addition to receiving user input, the interaction device 110 may also provide for additional interaction with the remote computer 120 by providing a USB connection to a USB port 109 of the local computer 102. The USB connection allows the interaction device 110 to emulate USB devices for the local computer 102, such as additional storage devices including devices that the local computer 102 may use when booting-up. For example, the remote computer 120 may provide a floppy, CD-ROM, or hard disk drive that contains a boot-up sequence to be used by the local computer 102. Upon a connection being established over the network 118 between the interaction device 110 and remote computer 120, the local computer 102 may boot from a media source of the remote computer 120 with the boot-up sequence provided through the USB port 109.” (Col. 5, lines 27-41.)
In another example, U.S. Pat. Appl. Pub. No. 2007/0174526, entitled “Virtual media system, method and devices”, describes a KVM system which provides for USB devices to be accessed by target computers: “A KVM switch connects a client with a target server via a network, the client computer having at least one device attached thereto. A second mechanism connects to a USB port of the target and communicates with the target using a USB protocol. A client mechanism communicates with the second mechanism via the network. A virtual media mechanism enables the target server to access the USB device attached to the client.” (Abstract.) This method allows a physical storage device attached to the client computer, such as a floppy drive, CD drive, removeable disk, etc. to be mapped as a virtual drive on the target computer. (See, e.g., FIG. 6(c) and paragraphs [0267]-[0270] of this publication.)
For consistency, in this disclosure, the computer to which the storage device is physically attached is referred to as the client computer or client, and the computer to which the storage device is mapped as a virtual medium is referred to as the server computer or server.
Conventional virtual media methods only allow an entire physical storage device (or possibly a logical drive if the storage device is partitioned) to be mapped as a virtual drive on the server. This method, referred to herein as disk-mount, has many disadvantages, such as poor reliability and poor security. For example, the content of the entire storage device (or drive) would be accessible to the server, so the client is unable to protect the confidentiality and security of contents on the storage device. Further, when write-back function is implemented in a disk-mounted system, when an error occurs during a write operation, such as an error due to network transmission, there is a risk of crashing the storage device.